The headers and imports libs are written for MSVC and most other compilers have ported versions. Do you know anyone with a broadband connection that can download it and burn it on CD for you? The documentation is far easier and faster to use than looking up MSDN.

If you just need the occasional value you can download lcc-win32. The headers will not be compatible with your compiler but you can extract values that you need. The download is under 4MB.

Or you can look on the web, although these seem to be out of date:
Search: winuser.h site:doc.ddart.net